Modelling by the experimental design for color removal (Absorbance at 254 nm) from tannery wastewater

Abstract

This article is devoted to the results obtained during the physicochemical treatment of colored indus-trial tannery discharges of the city of Moahammedia by coagulation flocculation. The volume of settled sludge is measured and the supernatant is recovered for the determination of the color of the treated water, this one is measured on samples previously filtered through fiber membranes. The effectiveness of color removal was investigated by measuring the absorbance at 254 nm. We were interested in the application of the methodology of screening experimental designs on the param¬eters that influence the color of treated water. Six factors with different modalities were identified, such as: five factors (coagulant, coagulant concentration, flocculant concentration, ash concentra¬tion and pH) with two levels, and one factor (flocculant) with seven levels. The influence of these parameters on a response accommodated at the exit was highlighted. The derivation of a theoretical model has been realized. A series of experiments is carried out. The analysis of our results, based on a statistical approach, is presented. The parameters that have a significant influence on the outputs have been identified. Thus, the input factors such as: coagulant and pH have a large influence on the measured response at the outlet (the absorbance at 254 nm). This allowed the validation of the model. The theoretical and experimental results are very convergent. Furthermore, the results of our paper demonstrated that the approach used is promising in terms of the low time, cost and equipments; that have been used to carry out the test.